Process of preparing amines and nitriles from ammonia and olefins



Patented Aug. 29, 1950 PROCESS OF PREPARING AMINES AND NITRILES FROMAlWlVIONIA AND OLEFIN S John W. Teter and Leonard E. Olson, Chicago,Ill., assignors to Sinclair Refining Company, New York, N. Y., acorporation of Maine No Drawing. Application August 31, 1946, Serial No.694,434

4 Claims. (Cl. 260-4653) This invention relates to improvements in theproduction of nitrogen-containing products, particularly nitriles, bythe direct catalytic reaction of olefins with ammonia. It includesimprovements in the process and improved catalysts which are moreeconomical than the catalysts heretofore considered most effective inpromoting' the production of nitrogen-containing products, particularlynitril'es of low molecular weight, while effectively serving to promotethe reaction and give high yields of the desired products Whilerepressing to a, substantial extent pyrolitic decomposition reactions ofthe hydrocarbon, such as cracking and polymerization, with production ofhydrocarbon polymer, tarry and carbonaceous material and the like.

The production of nitrogen-containing products, particularly nitriles,by the catalytic reaction of ammonia with olefins, and catalysts usefulfor that purpose, have been described in Patents 2,381,709, 2,381,470,2,381,471, issued August 7, 1945; 2,392,107, issued January 1, 1946;2,418,562, issued April 8,- 1947; 2,406,929, issued September 3, 1946;2,398,899, issued April 23, 1946, and Teter application Serial No.444,095, filed May 22-, 1942, now abandoned. Teter application SerialNo. 605,832, filed July 18, 1945, now abancloned, describescobalt-containing catalysts which are particulariy effective. In suchprocesses, temperatures ranging from about 400 F. to about 725 are used,temperatures of about 640 to 650 Ft being particularly useful where theolepropylehe, with somewhat higher temperatures representing the mosteffective range where the olefin ethylene. Catalysts which have beendescribed as useful in this procedure in general include reduced metaloxides deposited on an inert carrier. The easily reducible metals,cobalt, nickel, and iron, have been described as most useful, withcobalt outstanding.

The present invention provides improvements in this process whichinvolve the use of highly efiective catalysts which are less costly thanthe cobalt catalysts which have heretofore been regarded as the mosteiiective catalysts. It includes these catalysts and their preparation.The advantages of the invention lie in a high yield ornitrogen-containing product's, particularly the desired nitriles, basedupon olefin feed and olefin consumed, long catalyst life, relatively lowproduction of secondary or waste products, and or particular importance,low catalyst costs.

The catalysts used in the practice or the invention are reduced metaloxide catalysts containing cobalt and another metal of the type which,in oxide form, has the capacity of forming spinel-type crystalstructures, with cobalt oxide, deposited on an inert carrier, such asdiatomaceous earth, titanium dioxide, heat-treated bentonite,heat-treated magnesium silicate, aluminum oxide, either as bauxite orcorundum, deactivated by heating, or the like. While the effectivecatalytic material in the new catalyst is the reduced metal oxide,consisting of an admixture of reduced cobalt oxide and the oxide of theother metal, the exact structure of the catalytic material in thecatalyst is not known, nor is it known whether, in the course ofpreparation of the catalyst, a spinel-type crystal structure at any timein fact exists. It is, however, metals of the type which in the form oftheir oxides, form spinal-type structures with cobalt oxides, which areincluded in the new catalysts in association with the reduced cobaltoxide.

In general, in the new catalysts, the cobalt and the other catalyticmetal will be included in proportions such as correspond to theproduction of spinel-type crystals when the metals are in the form oftheir oxides; that is, in general, the molar proportions of cobalt andother metal will range from about 1:2 to about 2:1, although somewhatless of the second metal, or even more, can be included in the catalystwithout departing from the invention. The proportions of metal and inertcarrier of the finished catalyst will in general be such that aboutone-half the weight of the finished catalyst is reduced metal oxide,although it will be understood that the metal may be used in larger orsmaller proportions than this.

In general, in the new catalysts, it is desirable to keep the sulfatecontent low, usually not exceeding 0.2%, and the chloride content low,not exceeding about 0.1%. Sodium, in small quantities, appears to be anactivator or promoter, and may be present in quantities ranging from afraction of 1%, e. g., 0.2% to 0.3% up to 3% or 4%, or even somewhatmore. In general, the promoting efiect of sodium becomes particularlynoticeable when the amount of sodium exceeds about 1%.

The new catalysts are advantageously prepared in the form of smallagglomerates or granules, as by pelleting or extrusion, after depositionof the metal on the inert carrier, and in the process, willadvantageously be used in the form of a fixed bed, with the mixturecontaining the ammonia and olefin being passed through the bed.

The new catalysts are capable of reactivation by hydrogen after havingbeen onstream for a period of time sufficient to cause the catalyst tolose some of its initial activity, and may be used with advantage in thecyclic process described in Patent 2,419,470, issued April 22, 1947, inwhich two or more reactors are used in parallel, with one reactoronstream while the other is being reactivated by passing hydrogenthrough it followed by an ammonia purge. In general, in using the newcatalyst, it is advantageous to include a small amount of water in thefeed to maintain the catalyst in its most effective condition, asdescribed in Patent 2,417,893, issued March 25, 1947. It is alsoadvantageous to use a large excess of ammonia in the process, asdescribed in Patent 2,417,892, issued March 25, 1947.

1A number of metals, other than cobalt, which in the form of oxides, canform spinel-type crystal structures with cobalt oxide, may be used inthe practice of the invention. Of particular importance are nickel andzinc, either of which may be used alone along with thecobalt. Effectivecatalysts may also be'produced involving the use of both nickel and zincalong with the cobalt, Other metals which may be used include manganese,copper, iron, magnesium, calcium, barium, strontium, and aluminum, andthese may be used along with the cobalt, or various mixtures may be usedwith the cobalt. In general, if one or more than one of the metals otherthan cobalt are included in the catalyst, the proportion of theadditional metal used will be such that the molar ratio of cobalt toother metal, or where more than one metal is used, metals lies between1:2 and 2:1.

The newcatalysts are prepared by depositing the catalytic metal on theinert carrier, for example, as the hydroxide or carbonate, calcining theresulting material to convert the metal to the oxide or mixture ofoxides, and then reducing the resulting metal oxide with hydrogen. Theexact structure of the resulting reduced metal mixture is not known.That is, it is not known whether in the active catalyst, the metal ispresent as such, or whether part of it is present as such, with theremainder present as an oxide, or mixture of oxides, or whether theeffective catalytic material represents some equilibrium mixture ofmetal, and one or more metal oxides. The reduced metal catalyst ispyrophoric, and ferromagnetic, and there are indications that it doescontain definite proportions of both metal and metal oxide, and it maybe that the active catalyst is metal activated by metal oxide, or theactive material may be an intermediate oxide. The fact that theintroduction of water along with the hydrocarbon and ammonia feed helpsto maintain the catalyst at it greatest activity indicates that theactive material may be a metal oxide or an admixture of metal with oneor more oxides in some type of equilibrium influenced by the water.

The improved catalysts are advantageously prepared by depositing themetals, i. e., cobalt and one or more other metals, on the inert carrierby reaction of a mixture of the soluble metal salts with caustic soda orsodium carbonate in the presence of the slurried carrier. Cobaltsulfate, and the sulfate or other so uble salts of the other metal ormetals, will ordinarily be used because of cost, but in general, thenature of the salts selected is not of great significance. Of course,where metals like calcium are used along with the cobalt, it is notdesirable to use cobalt sulfate because of the possible formation ofcalcium sulfate in the catalyst, which would make difficult or preventthe reduction of the sulfate content to the desired low level in thefinal catalyst. After the cobalt and other metal or metals are depositedon the carrier in the form of the hydroxide or carbonate, the product iswashed with demineralized water to remove soluble salts, and inparticular, to remove sulfate and chloride ions, and is then calcined,pelleted, and reduced. Ordinarily, final reduction will be carried outin the reactor, although it is possible to reduce the catalyst inanother vessel, and then stabilize it in the known way fortransportation. A typical preparation of a catalyst of the inventionwill be illustrated by the following example.

ExampZe.A suspension of diatomaceous earth (Celite #337) in aqueoussodium carbonate containing 540 grams of the earth and 910 grams ofsodium carbonate per gallon was prepared. The slurry was settledovernight and then heated to C. with live steam. To it was added anequal volume of a solution containing 1275 grams of cobalt sulfateheptahydrate (COSO4.7H2O) and 597 grams of nickel sulfate hexahydrate(NiSO4.6H2O) per gallon, corresponding to a cobalt-nickel ratio of 2:1.The addition of the salt solution took place over a period of hour withintermittent high-speed agitation. The precipitated mass was stirred foranother /2 hour and was then filtered. The filtered cake was dried at0., ground, and washed, by repeated slurry and, filtration, until thesulfate content was reduced to less than 0.1%. The cake was then dried,ground, calcined for two hours at 660 F. and pelleted, using 4% graphiteas a lubricant. The catalyst was then introduced into a reactor andreduced, by purging with ammonia at 3,000 lbs. for two hours, thenpassing in hydrogen at atmospheric pressure for 12 hours, purging withammonia at 3,000 lbs. for two hours, passing in hydrogen at atmosphericpressure for 8 hours, and then at 3,000 lbs. pressure for 4 hours,followed by purging with ammonia at 3,000 lbs. for 6 hours, thisoperation beingcarried out at 640 F. The sodium content of the catalystwas adjusted, prior to calcination, by the addition of sodium acetate,and in the catalyst was 1.95%.

The catalyst so prepared was then used in the production ofnitrogen-containing products from a mixture of ammonia and hydrocarbon,the hydrocarbon being a typical PP fraction containing 41.4% ofpropylene with the remainder largely propane, with some ethane andhigher hydrocarbon. The molar ratio of ammonia to olefin in the feed was10:1. The olefin space velocity was 0.2. The temperature was 640' F.,and the pres: sure 1500 lbs. per square inch. The operation was carriedout in a cyclic manner, in accordance with the process described inTeter application. Serial No. 558,484, now Patent No. 2,419,470 withintermittent 6 hour onstream and reactivation periods. The yield ofnitrogen-containing prod' ucts was 27.8%, calculated as propionitrile,and based on olefin feed. The catalyst showed a high activity and longlife.

Other catalysts, prepared in essentially the same manner, but withdifferent active catalytic materials, were also tested. Thus, a catalystprepared in the same manner but using zinc nitrate and cobalt sulfate,in proportions to give a catalyst with a cobalt-zinc molar ratio of 2:1,gave a yield of 25% nitrogencontaining products calculated aspropionitrile. Another catalyst prepared with cobalt sulfate andmanganese acetate, in proportions to give a. cobalt-mamganese molarratio of 2:1 gave a yield of 12.9%. Another catalyst prepared withcopper sulfate and cobalt sulfate, in proportions to give a cobaltcoppermolar ratio of 2:1, gave a yield of 15.3%.

stood, and the reference herein to metals, which in the form of oxides,can form spinel-type structures with cobalt oxide is not intended toimply that such structures are in fact produced A catalyst prepared fromcobalt sulfate and mag- 5 or present, but rather to define the type ofmetal nesium sulfate, in proportions to give a cobaltwhich serves aseffective catalytic material when magnesium molar ratio of 1:2, gave ayield of in association with reduced cobalt oxide in the 19.3%. Acatalyst prepared from cobalt sulfate, catalyst. zinc nitrate, andnickel sulfate, in proportions to We claim: give a zinc-cobalt-nickelratio of 1:1:1, gave a 10 1. A catalyst effective in the production ofyield of 27.8%, and a catalyst prepared from zinc nitrogen-containingproducts by the direct renitrate, cobalt sulfate and nickel sulfate, togive action of ammonia with olefin, said catalyst conazinc-cobalt-nickel molar ratio of 1:4:1, gave a sisting essentially ofan inert carrier and, supyield of 27.8%. Typical data with respect tothe ported thereon, a reduced metal oxide catalytic catalyst in thesevarious runs and the operating material including reduced cobalt oxideand reconditions of the runs, are given in the follow duced zinc oxide,the molar proportions of cobalt ing table: 7 and zinc being between 1:2and 2:1.

Table Catalytic metal Cuzo Znz2Co MnzZOo 2Mg1Co Niz20o ZnzCozNiZn:4Co:Ni

Na content 0.82 0. 50 0. 79 0. 41 1. 95 0. 27 0. 37 so. content.-. 0.020. 01 0. 01 0. 005 0. 040 0.102 0.115 Temp, "F- 040 040 640 040 040 640040 Pressure, #/sq.1n 1, 500 1, 500 1, 500 1. 500 1, 500 1, 500 1, 500Olefin sv (L' .vvm. V.l1r 0.22 0.19 0. 23s 0. 0.21 0.2 0.2 NHazOlefinratio s. 97 11.2 s. 75 10. 10 10. 9 11 1120 in NHa, Wt. Percent 0. 2 0.20. 2 0.2 0. 2 0. 2 0. 2 Percent OlefininHO 41 41 40 40.2 40.2 39.5 40.2Yield, Percent 15. a 25 12. 9 19. 3 27. s 27.8 20. 2

It will be noted that the catalysts containing 2. A catalyst effectivein the production of zinc and cobalt are particularly effective. Onenitrogen-containing products by the direct reacof the most eiiectivecatalysts contains nickel, tion of ammonia with olefin, said catalystconzinc and cobalt in molar ratios of 1:1:1, and such sistingessentially of an inert carrier, and, supa catalyst is of particularadvantage because it ported thereon, a reduced metal oxide catalyticcontains but one-third the amount of cobalt that material consisting ofthe reduction product of an active cobalt catalyst contains, and thusmay mixed cobalt, nickel, and zinc oxides, the molar be prepared at avery much lower cost, a factor proportions of cobalt and of combinednickel of great importance in the process, because cataand zinc beingbetween 1:2 and 2:1. lyst cost, despite reactivation and oxidative re-.111 a process for producing nitrogen-containgeneration, is a major itemof expense in the ing products from ammonia and olefin the imamin tionprocess, provement which comprises passing a mixture The catalystsdescribed in the foregoing excontaining ammonia and the l th mample haveconsisted of the catalytic metal demonia being present in bs a ESS,posited on diatomaceous earth. Other inert supthrough a y of theCatalyst fi ed in Claim porting materials may be used to give catalysts1 While maintaining a temperature within the which are effective. Thus,instead of the diatorange from about 400 F. to about 725 F. in themaceous earth, other porous carriers, such as region of catalystcontact. heat-treated bentonite, heat-treated magnesium 4. In a processfor producing nitrogen-containsilicate, and alumina, including nativebauxite ing products from ammonia and olefin the imand corundum, inparticular after deactivation provement which comprises passing amixture by heating for example to 1100 F. for one hour containingammonia and the olefin, the amor more, may be used. Also, non-porousinert monia being present in substantial excess, carriers such astitanium dioxide may be used. through a body of the catalyst defined inclaim 2 In general, the use of any of these carriers inwhile maintaininga temperature within the volves no modification of the techniqueinvolved range from about 400 F. to about 725 F. in the in producing thecatalyst or in its handling for region of catalyst contact. use. JOHN W.TETER.

The important characteristic of the catalysts LEONARD E, OLSON, of theinvention lies in the combination of the reduced cobalt oxide with thereduced oxide of REFERENCES CITED another metal which, as the oxide, canform spinel-type crystal structures with cobalt oxide. fi gt wreferences are of record m the It is not necessary that, in the courseof produc- 1e 0 15 tion of the catalyst, such spinel-type crystal UNITEDSTATES PATENTS structures actually exist at any time, and, indeed, inview of the fact that even in the calcining 1 3332 J Name Date aegerAug. 1, 1933 operation, the temperature to which the catalyst 2 101 104S .1711 t 1 D 193,7 is subjected never exceeds substantially the temm1 8a perature used in the reaction, and indeed, may 2274639 scheuermann at1942 not exceed about 650 F., although higher tem- 2,331,968 Forney 19,1943 peratures may be used, indicates that there may 2,339,927 Heckel25, 1944 be doubt that a spinel-type crystal structure ever 2,370,797Kearby 6, 1945 is produced. The mechanism of the catalytic 2,331,473Teter 1945 effects of the material, and the structure of the 2,381,709pgar et al Aug- 1945 catalytic material itself, are not yet fully under-2,398,899 Teter Apr. 23, 1946

1. A CATALYST EFFECTIVE IN THE PRODUCTION OF NITROGEN-CONTAININGPRODUCTS BY THE DIRECT REACTION OF AMMONIA WITH OLEFIN, SAID CATALYSTCONSISTING ESSENTIALLY OF AN INERT CARRIER, AND, SUPPORTED THEREON, AREDUCED METAL OXIDE CATALYTIC MATERIAL INCLUDING REDUCED COBALT OXIDEAND REDUCED ZINC OXIDE, THE MOLAR PROPORTIONS OF COBALT AND ZINC BEINGBETWEEN 1:2 AND 2:1.
 3. IN A PROCESS FOR PRODUCING NITROGEN-CONTAININGPRODUCTS FROM AMMONIA AND OLEFIN THE IMPROVEMENT WHICH COMPRISES PASSINGA MIXTURE CONTAINING AMMONIA AND THE OLEFIN, THE AMMONIA BEING PRESENTIN SUBSTANTIAL EXCESS, THROUGH A BODY OF THE CATALYST DEFINED IN CLAIM 1WHILE MAINTAINING A TEMPERATURE WITHIN THE RANGE FROM ABOUT 400*F. TOABOUT 725*F. IN THE REGION OF CATALYST CONTACT.